Telephone system



June 18, 1946.

W. T. POWEL L TELEPHONE SYSTEM Filed Aug. 24, `1944 2 Sheets-Sheet 1CENTR/7L OFF/CE CODE TABLE 2" STE/7 STAT/0N INVENTOR.

WIA/FRED 7. POWELL ETTORN'Y /2345678 ff/@.rkrn P E v /rRRrrRR y pMrrrrRRRR C Junc 18, 1946. w."r. POWELL TELEPHONE SYSTEM Filed Aug. 24,1944 2 Sheets-Sheet 2 C011/ TIPOL POINT Patented une 18, 1946 UNITEDsTATEs PATENT OFFICE vStromberg-Carlson Company,

a. corporation of. New York.

' i "Application v"'IIhis invention relates 'to telephone systems of v'I' either the manual 0r automatic type.

In the operation of telephone systems it is frequently desirable toprovide telephone service to a small group or community of remotelylocated subscribers. Due to the remoteness of this group from theexchange, it is expensive to extend individual linesto Said subscribers.While 'multi-party lines have .been used in such situations',`multi-party service has real limitations, such as lack of secrecy, andwhen more than four subscribers are assigned to a given line, theresulting service frequently becomes most vunsatisfactory.

In accordance with the main feature ofthe present invention, there isprovided a secret service arrangement whereby a small group or communityof subscribers remotely located with respect to the central exchange canbe served over a singletel'ephone line.

The' drawings comprising Figs- 1 and 2', when arranged side by side inthe order named, dia- 'gramm'atically illustrate a portion of atelephone system incorporating the present invention. Fig. 1, whichshows the portion of the system located -at the central oiiice,illustrates in its upper `portion, the finder multiple of a multistationtelephone' line, the connector multiple of this line with a sleeveconductor and cut-off relay for each station on the line as well as thecode conductors associated with the line; In the lower .left-handportion of Fig. 1, there is shown a, code table giving the combinationsof pulses respectivelyl applied to the tip and ring conductorsof thetelephone line to effect the selection of stations thereon. In the lowerright-hand portion'oi` Fig. l1, there is illustrated a primary countingrelay chain and control relays cyclicallyoperating the relay chain toapply code conditions from the code conductors to the respective tip andring vconductors of the telephone line. Fig. 2, which shows the portionof the system located at the remote control point, illustrates eighttelephone stationsV of the mentioned Vmultistation line, as well as setsofl line relays and of the stations relays, a line relay and aV stationsrelay of a'rset being individual to each telephone station. In the lowerpart of Fig. 2, there is` shown a secondary chain of counting relays'andassociated control relays for operating -these counting-relays instep-by-step relation with .the corresponding counting relays. of theprimary chain at the central office;

It is believed that the operation of the system will bestbra-understoodl by describing the extenlRochester, N.'Y.,

sion of an originating call from one of the sub-l stations of the groupor community of subscribers and then by describing the extension of aIcall from the remote exchange to one of the-stations of the`group. y YvLet it beassumed that the subscriber at station #.lremoves his receiverfromvits lswitch-hook to initiate acall. This is effective togenergize aline relay 5 (Fig. 1) and theline relay 6 individual to the callingsubstation (Fig. 2). This circuit exf tends from a negative pole ofbattery, winding of the v-line relay 5, back contact and armature laofthe common cutoffrelay 1, armaturesv, 9 and IIJ 'and back contacts' ofthe secondary counting relays II, I2 and I3 respectively, con? ductor I4, upper winding of the relay B, back Contact and armature of the rststations relay 6a,ring side of the calling line and through thesubstation, thence over the tip side of thecalling line, armature andback contact of relay 6a, conductors I6 and ILarmatures I9, 20 and 2land the back contacts of relays I3, I 2 and I I', tip

side 23 of the telephone line extending from the community to thedistant exchange, armature 425 and'back contact ofthe common cut-offrelay 'l, to the positive side ofbattery. The operation ,of the linerelay 5 is effective to cause an idle trunk to be connected to thecalling line. v-ln the .present instance, the switching means comprisesa finder (notshown) which is controlled .by certain marker-relays (notshown) in -themanner illustrated in thePowell Patent 2,325,877, grantedAugust 3, 1943, to seize the calling line. Theoperation ofthe'lineurelay6 at the community .is

effective-to interrupt a series circuit'and a step line with its relay26 (Fig. 2), to be described. This series circuit extends from thenegative pole of battery at the remote exchange (Fig. l), conductor 2l,winding of the relay 26, conductor 28, back contacts and lower armaturesof the relays 6, 29, 3D and 3l, conductor 32, back contacts andarmatures'of `relays 34, 35, 36, 31,.conductor 39 herein referred to asthe step line which extends to the remote oiiice where this circuit willbe completed to the positive pole of battery ln the :furthercourse ofextending connection. As has ybeen mentioned, the relay 6 at its lowerarmajductor 39. This is effective to complete a locking 3 circuit forthe line relay 6 (Fig. 2), the circuit being completed from the positivepole of battery at the armature 43, conductor 39, armatures and backcontacts of relays 31, 36, 35 and 34, conductor 32, armature and backcontacts of relays 3|, 36 and 29, armature, front contact and lowerWinding o i relay l6, lower winding of station relay 6a, conductor 21 tothe negative pole of. battery. When the station relay 6a operates, itextends the calling line over the talking conductors 44 and 45, to thearmatures 2| and 8 of the relay Relay is operated from the negative poleof battery, winding of this relay, conductorv46, front contact andarmature of relay 6, lback contacts and armatures of relays 29, 30 and3|, conductor 32, back contacts and armatures of relays 34, 35, 36 and31, step line conductor 39, armature- 43 and front contact, to ground.With the relay,

thus operated, the talking `conductors 44"'andl 45 of the line areextended through the front contacts and armatures 3 and 2|l to thetelephone line including the conductors 23 and 24 which extend to theremote or central oflce'. When the relay 42' (Fig. l) operates over thesleeve conductor 4I, it closes a circuit for the common cut-off relay 1,through the armature 48 and front contact of relay 42, to the positivepole of battery. The common cut-off relay 1 on operating extends thecalling line through its armatures 2'5 and la and front contacts, andthence through the armatures and back contacts of either or both relays50 and 5|, armatures and back contacts of the primary counting relays52, 53* and 54, and conductors 51 and 58 to the finder multiple. Thecommon cut-ofi relay 1 interrupts the circuits of the cut-oli relays 60,6|, 6'2, 63, 64, 65, 66 and 61 of the eight numbers used for terminatingcalls to the eight stations of the community group. At the same time,the relay 1 applies ground potential to the sleeve conductors, such as68, 69, 10, 1|, 12, 13, 14 and of all these terminals in the connectormultiple so that these terminals are rendered busy to incoming calls.Dial tone may be extended to the calling line when the finder extends anidle link circuit to this line. On hearing the dial tone, the callingsubscriber may proceed to dial the wanted number of the line terminatingat the remote exchange, this portion of the operation of the systembeing effective in the manner Well-known. It should be understood thatthe' operation of any line relay, such as 6', 29, 35, 3|, 34, 35, 36 and31 causes the cir-cuits to function in the manner above described forextending the associated line to the common tip and ring conductors 44and 45 by operating the associated stations relay, such as 6a, 29a,30a', 3|a, 34a, 35a, 36a and 31a. These station relays correspondsomewhat to cut-ofi' relays since there is one for each subscriber'sstation serving to disconnect the associated line relay winding. Forexample, the stations relay `6a of the calling line, underconsideration, at its inner upper armature and back contact disconnectsits'associated line relay 6 from the line These station relays alsofunction to connect its individual line Whether it s calling or Whetherit is being called, through to the common talking line circuit includingthe conductors 44 and 45 which in turn lead to the central or remoteoiice. Further, these station relays are selectively operated in thecase of a terminating call to select the wanted station.

At the termination of the connection from the central exchange, groundpotential is removed from the sleeve conductor 4| which is effective torelease the relay 42. The relay 42 in turn at its armature 48 interruptsthe maintaining circuit oi the cut-oli relay 1 which releases. Therelease of the relay 42 is also effective at its armature 43 to removepositive potential from'the step line including conductor .39. This iseffective to release the operated line relay 6 and the operated stationsrelay 6a, as well' as the secondary counting relay The release of theserelays restores the system to its normal condition.

I let it be assumed that a subscribers line, not shown, but located atthe central exchange, desires to establish a. telephone connection tothe station #1 ofthe group or community. 'I'hat calling subscribers lineis extended by usual switching means to the connector tip and ringmultiplejl, 18 and the sleeve terminal 68. It should be pointed out thatany of the illustrated stations 1 to 8 may be assigned any numberdesired in the central oflice but it 'is necessary to connect the sleeveconductors of the connector multiple of these numbers to. the sleeveconductors, such as 68 to 15 inclusive at the left of Fig. 1. This meansthat the tip and ring conductors, such as 11 and 18 of all these numbersare connected together but that individual sleeve conductors areprovided for this line. Since the wanted. subscriber is assumed to be atstation #1, ground potential Will be applied to the sleeve lconductor 68of this line, the ground potential being applied through the connectorat the central oflice. This ground potential is applied in a circuitthrough the make-before-break contacts ofthe cut-ofi relay 60, conductor19, armature and back contact of the cut-ofi relay 1, conductor 80,winding of the cut-01T relay 6U, to the negative poleof battery. Relay6D on operating closes a locking circuit for itself through its innerarmature and front contact and sleeve conductor 68. It will be notedthat the common cut-ofi relay 1 at its armatures and back contacts opensup the possible operating circuits of cut-off relays 68 to 61 inclusive.Relay 1 at its front contacts and armatures applies ground potential tothe sleeve conductors 69 to 15 inclusive for making these lines busy.The common cut-01T relay 1 at its armature 8l and front contact closes acircuit from positive pole of battery, armature and back contact of therelay 50, winding of relay 82, armature 8| and front contact of cut-offrelay 1, back contact and armature 43, step line conductor -39 andthencev through the armatures and back contacts of relays 31, 36, 35 and34, conductor 32,A armature and back contacts ofrelays 3|, 30, 29' and6, conductor 28, winding of relay 26, conductor 21, to the negative poleof battery. This circuit is effective to operate the relay 82 at thecentral olce and the relay 26 at the control point. The relay 82completes an obvious circuit for the slow to operate relay 84. Likewise,the relay 26 closes an obvious circuit for the slow releasing relay 85.The relay 84 locks itself operated as long as the common cut-orf relay 1is operated. Relay 84 closes a circuit for operating the relay 55, whichcircuit is traceable from .the negative poleof battery, Winding of thisrelay, back contacts and armatures of relays 54, 53 and 52, conductor86, front contact and armature-of relay 84, to the positive pole ofbattery. The slow releasing relay 50 is also operated at thisv time fromthe negative'pole of battery, winding of this relay, back contact 'andarmature of relay 52, back contact and armatureof relay 5|, conductor81, front contact and armature of relay 84, to the positive pole ofbattery. As soon as the relay 59 operates its armature 88, it opens upthe step'line circuit previously described which causes the relays 82and 26 to release. When the relay 82 releases, the relay 55 is heldoperated, from the negative pole of battery, Winding of this relay, itsinner front contact and armature, conductor 83, back contact andarmature of relay 82, oonductor 86, to the positive pole of battery atthe front contact and armature of relay 84. Relay 82 also closes acircuit for operating the relay 54 which circuit extends from thenegative pole of battery, Winding of relay 54, front contact andarmature of relay 55, conductor 89, front pole of battery. When relay 5Ioperates, it.

opens the energizing circuit ofthe relay 50, previously described. Relayon releasing closes its armature 88 and baci; contact to complete thestep line for operating the relays 82 and 25 connected in seriestherewith. When relay 82 operatesfit effects the release of relay 55.The operation of relay 28 effects the release of the relay 9D which' wasoperated as soon as'the slow releasing relay 85 Was operated. Likewise,

-relay I3 at the control point was operated by the release of relay 26.The release of relay .effects the release of the relay 5I and relay 5Iin turn again completes a circuit for operating the relay 59. Relay 50opens up the step line including the conductor 39, thereby releasing therelays 82 and 26. The release of the re,- lay 82 causes the operation ofthe relay 53. Relay 53 locks itself operated through its upper irontcontact and armature over conductor 86.

As soon as the relay 53 operates, it closes a circuit for operating theslow releasing relay 5I. This circuit now extends from the negative poleof battery, winding of this relay, armature and back contact of relay55, armatures and front contact of relays 53 and 54 to the positive poleof battery. When relay 5| operates, it again interrupts the operatingcircuit of the slow releasing relay 59 and this relay at its armature 88and back contact again energizes the step line 39 and the relays 82 and26 in series therewith. When the relay 82 energizes, it effects therelease of the relay 54. This relay at its lowermost armature and frontcontact interrupts the energizing circuit for the relay 5I, whichreleases. This in turn closes the circuit for again operating the relay50 which at its armature 88 and back contact interrupts the step line39. When the step line is interrupted, the relays 82 and 26 arereleased. This effects the operation of the relay 52 at the centralstation and the relay II at the remote control point. The circuit of therelay 52 is traceable from th'e negative pole vof battery, winding ofrelay 52, front contact and armature of relay 53, back contacts andarmaturesl of relays 54 and 55, conductor 89,

front contact and armature of relay 84, back contactl and armature ofrelay 82 to the positive pole of battery. Relay 52, on operating, locksitself operated through its upper front contact and armature, conductor86, front con- Vthe wanted station.

tactand armature of relay 84, to the positivev pole of battery. Therelay II at the remote control-point has its operating circuit completedfrom the negative pole of battery, Winding of relay II, front contactand armature of relay I2, back contact and armatures of relays I3 and96, front contact and armature of relay 85, back contact and armature ofrelay 26, to positive pole of battery. Relay 52 closes a circuit foroperating relay 5I. This circuit extends from the negative pole ofbattery, winding of relay 5|, armature and Vback contact of relay 55,armature and front contact of relay 53, front contact and armature ofrelay 52, back contact and armature of relay 54 to positive pole ofbattery. Relay 5I again interrupts the operating circuit of the relay 50whichl again releases. This again energizes the step line 39 whichincludes inseries therewith the relays 82 and 26. The operation of therelay 82 opens conductor 86 which has been maintaining the relay 53operated. Also, Wh'en the relay 26 at the control point 0perates, iteffects the release of the relay I2.

When the relay 53 releases, it causes the release,

of the relay 5I but the relay 50 is not energized at this time becauseits operating circuit .is interrupted due to the fact that the relay 53has released and the relay 52 is operated.

From the foregoing, it will be understood that the operation of therelays 82, 58 and 5| at the central oice passed through a cycle ofoperations in which the primary counting relays 55, 54, 53 and 52operate generally in the manner of the counting rrelay system disclosedin -the mentioned Powell patent. Similarly, at the control point, therelay 26 has a cycle of operations similar to that just described at thecentral ofce. During the course of this cycle, therelays 90, I3, |2 andII operate in sequence in the order named, also, generally in the mannerof the counting relay chain of the patent.

While the cycle of operations just referred to is taking place, stationselection to selectr the station #1, is also being eiected. It will berecalled that the relay 85 at the control point was operated at thebeginning of the cycle of operations. As soon as the relay 85 operated,it closed `a circuit for operating the conditioning relay 9|,

Aeight station relays will be operated depending on which one of the tipand ring conductors I4 and I'I is grounded at the central office as aresult of the operation of the cut-off relay of In the present instance,the station #1 is desired, cut-oil relay 60, therefore, is operated andthis relay at its armature 92 and front contact applies positivepotential through the back contacts and armatures of relays 54, 53, 52,5I and'59, conductor 23, arma- ',tures 2|, 20, I9 and back contacts, andthence through the armatures 9m, 9Ic, 9Ic,'9Ig to operate stationsrelays 6a; 29a, 30a and 3Ia. It will be understood that the four stationrelays just described will be operated when any one of the nrst fourcut-off relays 88 to 83 inclusive at the central station is operated. Inlike inaninclusive.

ner ifA any one of the last four cut-off relays, namely |54 to 61inclusive in the centraloflce is operated, the ring conductor 58 isgrounded for operating the second half of the station relays at thecontrol point, namely, relays 34a to 31a When the relay 26 is releasedat the end of the conditioning impulse, the conditioning relay 9| isreleased and does not operate again during the cycle. It has beenmentioned that the rst four station relays were operated by theconditioning impulse. It is now necessary to release all of theseoperated stations relays except station relay 6a related to the station#1, which relay must be maintained operated for selecting the #lstation. Station #l is indicated as the wanted station by the operationof the cut-oir relay S3 at then central station. When the relay 2G, atthe control point, releases at the end of the conditioning impulse, acircuit is closed for locking the first four station relays. Thiscircuit is traceable from ground, armature and front contact of relay85, continuity spring and back contact of relay 26, conductor 93,armature and front contact and lower winding of the relay 3Ia, conductor21 to grounded battery. Similarly, the relays 39a., 29a and 6a are lockoperated in multiple through their armatures, front contacts and lowerwindings in the same manner as relay 3 I.

At the beginning of the first impulse following the conditioningimpulse, during which relay 9| was operated, the relay 26 is againoperated and at its continuity spring and back contact it opens thelocking circuit just described for the four stations relays. However, aselecting locking circuit is closed for the stations relays 6a, 29a forpreventing the release of these relays. This circuit extends from groundon the tip line conductor |58 applied through the front contact andarmature of the relay 54, back contacts and armatures of relays 53, 52,and 50, front contact and armature 25, conductor 23, armature 2| andback contact, armature and back contact, armature I9 and front contact,conductor 95, lower armature, front Contact and upper winding of relay6a, conductor 21 to grounded battery. Also, this ground is extendedthrough the armature 94 and front contact of relay I3, conductor 95,lower armature, front contact and upper winding of relay 29a, conductor21, to grounded battery. The #l and #2 station relays 6a and 29a areheld operated in this circuit but no similar holding circuitI isprovided for the stations relays a and 3| a so that these last namedrelays release. When in the course of the cycle, relay 26 releases atthe end of the first impulse period, the locking circuit including thelower windings of relays 6a, and 29a is completed for these relays. Atthe beginning of the second impulse, the operation of the relay 26 opensthe locking circuit including the lower windings of relays 6a and 29a.The #2 station relay 29a releases because no circuit is completed atthis time for its upper winding since the relay I3, which previouslycompleted the circuit for relay 29a at the armature 94 and frontcontact, is released. However, relay I2 is now operated and at itsarmature 20 completes a circuit for maintaining the #l stations relay 6aoperated during the second impulse period. This circuit extends from thepositive pole of battery, armature 91 of the cut-off relay 60, conductor98, front contact and armature of relay 53 now operated, back contactand armatures of relays 52, 5I and 50, .tip conductor 23, armature 2land back contact of relay II, armature 20 and front contact of relay I2,conductor 95, lower armature and front contact and upper Winding ofrelay 6a, conductor 21 to the negative pole of battery. The potentialapplied at the armature 91 of cut-01T relay 60 is ineffective to affectthe #3 stations relay 30a and the #7 stations relay 36a, both of whichare released at this time.

When the relay 26 is released at the end of the second impulse period, alocking circuit is completed for the #l stations relay 6a from ground atthe armature and front contact of relay 85, continuity spring and backcontact of relay 26, thence over conductor 93, lower armature, frontcontact and lower winding of relay 6a, conductor 21 to grounded battery.Also, when the relay 26 is operated at the beginning of the last impulseto continuously energize the step line 3S, the #l stations relay 6a ismaintained energized from grounded battery, conductor 21, lower windingof relay 6a, its front contact and armature, conductor 93, front contactand armature of relay II, armature and continuity spring of relay 26,front contact and armature of relay to ground. As a result of the cycleof operations, including the transmission of impulses over the step linein the manner just described, the relay Ba is selected and maintainedoperated. Relay 6a at its upper armatures and front contacts extends thetip and ring conductors of the calling line to the conductors 44 and 45and thence through front contacts and armatures I8 and 2| of relayconductors 24 and 23, armatures and front contacts of the common cut-offrelay 1, armatures and back contacts of relays 59 and 5|, armatures andfront contacts of relays 52, tip and ring conductors 11 and 18 whichterminate in the connector switch. On the seizure of the called line,ringing current is applied to the called line to actuate the straightline ringer provided thereafter,

It is believed unnecessary to explain the operation in detail forselecting any one of the eight other lines illustrated. lt will besulcient to point out that the cut-off relay of each line applies groundin various combinations to conductors which are associated with the tipand ring side of the line during the various steps in the cycle. Byreferring to the code table shown in the lower left-hand corner of Fig.l, it will be seen how in the case of the rst station, ground is appliedto the tip conductor during the conditioning period, ground is alsoapplied over the tip conductor during the rst and second steps to selectstation #1. However, in order to select station #2, ground is appliedt'o the tip conductor during the conditioning step and during the rststep. However, during the second step ground is applied to the ringconductor to select the #2 station. These various combinations, asindicated by the code table, and which are determined by the operationof the cut-01T relay of the called line, selectively operate thestations relay of the called line to eiect the selection. v

The release of the connection at the central cnice removes ground fromthe sleeve conductor E8 to eiect the release of the cut-oil relay 50individual to the station and the common cut-off relay 1. The release ofthe relay .1 at its armature 8i opens up the step line 39 to effect therelease o1 relays 82 and 25. These last named relays cause the releaseof the slow releasing relays S and 85. These relays in turn eiect therelease of relays and l l so that the equipment is in its normalcondition.

What I claim is:

l. In a telephonev system, a telephone exchange, a pluralityof telephonelines terminating at said exchange, one` of said telephone linesextending to a remote control point and having a plurality of stationsthereon at said point, means for interconnecting said telephone lines, aplurality of sleeve conductors at said exchange, one sleeve conductorbeing provided for each station associated with said multi-station line,a group of selectively operable relays at the remote point efiective toconnect a wanted station to said multistation line to the exclusion ofother stations thereon, and means responsive to the seizure of thesleeve circuit individual to a wanted station onsaid line forselectively operating said relays to connect the wanted stationtelephonically to said multi-stationline. Y

.2. Ina telephone system, a telephone exchange, a-plurality of telephonelines terminating at said exchange, a multi-station telephone lineterminating in a plurality of outlets at the exchange and extending `toa remote control point where it is provided witha station correspondingto each outlet, means for interconnecting said telephone.

lines, a group of selectively operable relays at theremote,point.eiectivetolconnect a wanted substation to saidmulti-station line to the exclusion of other stations thereon, and meansresponsive to the extension of a telephone line to a selected outlet ofthe multi-station line for selectively operating said relays to connecttelephonically to said multi-station line, the station thereoncorresponding to said selected outlet, to the exclusion of otherstations thereon.

3. In a telephone system, a telephone exchange, a plurality of telephonelines terminating at said exchange, a multi-station telephone lineterminating at the exchange and extending to a remote control pointwhere it is provided with a plurality of stations, said multi-stationtelephone line between said exchange and said control point comprisingonly two talking conductors and a control conductor, a plurality 4ofsleeve conductors local to the exchange, one sleeve conductor for eachstation associated with said multi-station line, means forinterconnecting said telephone lines, a group of relays at the remotepoint selectively operable in response to various series of code signaisand eiective to connect a wanted substation telephonically to saidmulti-station line to the exclusion of other stations thereon, meansresponsive to the seizure of the sleeve circuit individual to a wantedstation on said line for predetermining a series of code impulsesdistinctive of said last-mentioned station, and means governed'over saidcontrol conductor for effecting the transmission over said talkingconductors to said relays of said predetermined series of code impulses.

4. In a telephone system, a telephone exchange, a plurality of telephonelines terminating at said exchange, a multi-station telephone lineterminating at the exchange and extending to a remote control pointWhere it is provided with a plurality of stations, a plurality of sleeveconductors at said exchange, one sleeve conductor being provided foreach station associated with said multi-station line, means forinterconnecting said telephone lines. a group of selectively operablerelays at the remote control point, code conductors also associated withthe multi-station line at the exchange, means responsive to the seizureof the sleeve conductor of a wanted station on the multistation line forestablishing a code condition on certain of said codeconductorsdistinctive of said wanted station, and means responsive to theestablished code condition for selectively operating Asaidrelays tolconnect the wanted station telephonically to said multi-station line tothe exclusion .of other stations thereon.

5.` In a telephone system, a telephone exchange, a plurality oftelephone lines terminating at said exchange, amulti-station telephoneline terminating at the exchange and extending to a remote control pointwhere it is provided with a plurality of stations, a plurality of sleevecon-V ductors and cut-01T relays at said exchange, one sleeve vconductorand a cut-orfrelay electrically connected thereto for each 'stationassociated with said multi-station line, lmeans for interconnectingsaidtelephone lines, a group of selectively operable relays at the remotepoint, code conductors also associated with the multi-station line,means responsive to the seizure of the sleeve conductor and theoperation of its connected cuto relay individual to they wanted stationfor establishing a code condition on said code conductors `distinctiveof said Wanted station, and meansV responsive to the established codecondition forselectively operating said relays to connectl the-wantedlstation telephonically to said multi-station line to the exclusion ofother stations thereon.

6. In a telephone system, a telephone exchange, a plurality of telephonelines terminating at said exchange, 'a multi-station telephone lineterminating at the exchange and extending to a remote control pointWhere it is provided with a plurality of stations, a plurality of sleeveconductors and cut-oil relays at said exchange,` one sleeve conductorand a cut-off relay electrically connected thereto for each stationassociated with said multi-station line, means for interconnecting saidtelephone lines, a group of selectively operable relays at theremotepoint, code conductors also associated with the multi-station line,means responsive to the seizure of the sleeve conductor and theoperation of its connected cutoff relay individual to the wanted stationfor establishing a code condition on said code conductors distinctive ofsaid wanted station, means responsive to the seizure of the sleeveconductor and the operation of its connected cut-oil relay individual tothe wanted station for establishing code conditions on said codeconductors distinctive of said wanted station, a sender set intooperation by the seizure of any one of said sleeve conductors, saidsender operating to transmit said code conditions to the control point,and means responsive to the transmitted code conditions for selectivelyoperating said relays to connect the wanted station telephonically tosaid multi-station' line to the exclusion of other stations thereon.

7. In a telephone system, a telephone exchange, a plurality of telephonelines terminating at said exchange, a multi-station telephone lineterminating at the exchange in a plurality of outlets and extending to aremote control point where it is provided with a station individual toeach outlet, a plurality of sleeve conductors and cutoi relays at saidexchange, one sleeve conductor and a cut-oir relay electricallyconnectedthereto associated with each outlet, a group of selectively operablerelays at the remote point, code conductors also associated with themulti-station line at the exchange, means responsive to the seizure ofthe sleeve conductorand the oper-v ation of its connected cut-01T relayindividual to the Wanted station for establishing code conditions onsaid code conductors distinctive of said wanted station, a senderstarted into operation by theseizure of any one of said sleeveconductors, said sender including a chain of primary counting relaysoperating in sequence to transmit said code conditions to the controlpoint, and means including a secondary chain of countingfrelaysoperating in step-by-step relation with said primary chain of countingrelays, said secondary chain of counting relays operating to apply thetransmitted code conditions for selectively operating said relays toconnect the wanted station telephonically t said multi-station line tothe exclusion of other stations thereon.

8; Ina telephone system, a telephone exchange, a'iplurality of telephonelines terminating at said exchange, a multi-station telephone lineterminating at lthe exchange in al plurality of outlets and extending to`a remote control point where it is provided with a station individualto each outlet, a plurality of sleeve conductors and cut-off relays atsaid exchange, one sleeve conductor and a cut-off relay electricallyconnected thereto associated with each outlet, code conductorsV also`associated with the multi-station line at the exchange, a common linerelay at the ex-A change for all of said stations, a line" relay and astation relay for each station on said multi-station line, each stationrelay when operated serving to connect its station telephonically to themulti-station line, means responsive to the initiation of a call fromany of said stations for operating its line relay and said common linerelay, means responsive to the operation of the common line relay forextending the multi-station line in the direction of a wanted telephone,means responsive to the extension of the multistation line forcompleting a. locking circuit for the operated line relay, said lockingcircuit being serially completed at all of the other line relays, saidlocking circuit being also effective to operate the station relay of thecalling station, means responsive to the seizure of the sleeve conductorindividual to a wanted station of the multi-station line on theextension of a telephone line thereto for operating the cut-oi relay ofthe wanted station, said operated cut-oil' relay operating to apply to'said code conductors code conditions distinctive of said wanted station,means responsive to said code conditions for selectively controlling thestation relays to operate the station relay of the Wanted station to theexclusion of the other station relays.

WINFRED T. POWELL.

